01/09/13 18:31 Filed in: Inside an Engineer's Mind
We ListenIt's often assumed that someone with a visual impairment, such as blindness, has better hearing. While this person may collect more audible information than most of us, there is no physical advantage over someone with sight. That information is collected by the brain. That person has trained themselves to rely more on the remaining senses.
Did you ever discover a new fashion, car, or word, only to start noticing it over and over? "How did I not see that before? It was right in front of me all the time." It's the same with your ears. We audio engineers always talk about the psycho acoustics of the brain and it's ability to filter out unneeded sounds. Our ears hear our heart beat, the blood rush through the ear canals, and other body sounds, only to have them "psycho acoustically" removed by our brain. The same goes for straining to hear someone talk to you in a noisy room. You "psycho acoustically" filter out the other noise to only hear your friend.
Microphones are dumb. They have no brains. That wasn't an insult, but a fact. A microphone hears everything around it and can't filter out sounds. The housing is manipulated to make it more directional, but it still hears everything. That's where an audio engineer comes in. Our job is to pay attention to all the sounds that will cause problems later.
Most audio engineers are trained to hear offensive noises from the beginning. Hear that buzz? That air conditioning? That plane overhead? We first hear the sound isolated one-at-a-time so we will be able to hear it when it's buried under other sounds. When I was a music major, I became aware of this technique because I was able to pick out individual instruments during performances. I had been trained on trombone, but I could distinctly hear a clarinet, flute, saxophone, etc. when the whole band was playing, all because I was familiar with each instrument's sound.
There's another very important aspect of being an audio engineer. And that is to listen to what the client is saying. Sometimes the message is cluttered, unclear, or lacking in detail. But it is our job to understand what the creative goal is. Some people have difficulty expressing ideas in technical terms, but that's okay. We're not all nerds that only understand jargon (we just speak to each other that way). In fact, an emotive description is often the best way to communicate an idea.
Our motto "We Listen" embraces many ideas - technical, creative, inspirational, and personal. You should always know that we listen.
Did You Know?
- Fish do not have ears, but they can hear pressure changes through ridges on their body.
- The ear’s malleus, incus and stapes (otherwise known as the hammer, anvil and stirrup) are the smallest bones in the human body. All three together could fit together on a penny.
- The ear continues to hear sounds, even while you sleep.
- Sound travels at the speed of 1,130 feet per second, or 770 miles per hour.
- Dogs can hear much higher frequencies than humans.
- Ears not only help you hear, but also aid in balance.
- Snakes hear through the jaw bone and through a traditional inner ear. In essence, snakes have two distinct hearing mechanisms, which helps them hear and catch prey.
- Sitting in front of the speakers at a rock concert can expose you to 120 decibels, which will begin to damage hearing in only 7 1/2 minutes.
- Thirty-seven percent of children with only minimal hearing loss fail at least one grade.
- Male mosquitoes hear with thousands of tiny hairs growing on their antennae.
(The American Academy of Audiology, www.turnittotheleft.com)
Dynamix Tech Notes
With the exception of one or two particular microphones, all microphones are omni-directional. That is, they pick up sounds from all directions. A microphone that is uni-directional, like a shotgun or vocal mic, is one that has its housing modified. The diaphragm (the capsule that picks up the sound and turns it into electrical energy) can be surrounded by air vent slots in a tube to redirect sounds from the sides. For example, a sound from the left hits the left side of the tube that has the slots in it. Sounds are really waves of air, but they behave like ripples in water and spiral. When that sound from the left enters into the air vent from the left, it is spiraling in one direction. The remaining part of the sound wave from the left that isn't captured by the air vents enters the vent slots on the right side of the tube. Because these came in from the opposite direction, they are spiraling in the opposite direction. The two oppositely spiraling sound waves collide and cancel each other out. Any sound that came through the end of the tube (the front) has an open expressway to the capsule at the bottom.